2. You should looked al Phases, which are in Battle Phase and u will answer that yourself.There'r 4 main steps [and a few minor] - Start Step(announce that you enter in Battle Phase - last chance for cards like Formula Synchron,Throating Roar etc.),Battle Step(here u choose the target of your attack.Here you use yours Spell Sped 2 traps or spells - Mirror force,D.Prison,BoM etc.),Damage Step(kk the most gayest step in the game.He's the little moment between the hit of the monsters and the die of one of them.Here can be used ONLY Spell Speed 3 cards [Counter Traps] or cards, which specially designed the attack or defence of the monsters [Your favourite Honest or Shrink],then End Stape (End battle phase).

Just to further explain the answer.afaik, the last moment to activate Roar/Form Synch is when you declare an end to your main phase. if you/your opponent make a chain, you're not forced to enter battle phase and may redo your main phase ie: summoning/activating normal spell card etc.

on the battle step there's two sub-step, "Attack Declaration" and "Before Damage Step"a difference in this substep is that, this is the only moment you can activate card like mirror force, dimpris, etc(only 1 chain allowed in this substep, if your dimpris is 7 tools of bandit-ed, you can't activate another dimpris/MF due to an inferiority of spell speed, obviously trap stun works different since it's just spell speed 2). if you pass this step you go to before damage step.

in "Before Damage Step" sub-step card like MF/Dimpris can't be activated anymore, but you can activate book of moon/e-con or any spell speed 2 or higher that doesn't mention about activating it on "Attack Declaration" step. Multiple Chain may built here, if your book of moon is negated by said "solemn judgment", you can activate another book of moon after that chain resolve. And you will not go to the damage step unless both player agreed to leave the "before damage step" sub-step.

In Damage Step:there's actually 5 type of effect that can be activated in damage step, including quick effect monster that negate activation(Not negate an effect of a card and not make a card resolve without effect ie.D.D. Crow) effect that specificaly said to be activated in damage step, a BKSS-ed card, well actually a trigger effect monster that triggered in damage step also included ie: armageddon knight summoned by mystic tomato. and what that answer above given.

there's 7 sub-step in damage step, from sub-step 1 until 3, multiple chain can be built here,afterwards until the 7th sub-step only 1 chain can be built. The consequences of this is if you drop honest inb4 substep 4 ("During Damage Calculation") and your opponent chain with Divine Wrath/Chariot, you may drop another honest,(though now honest is limited =P), however, if your opponent also hold an honest in their hand, your opponent might as well drop it after your honest resolve, and his honest will win the battle.if you drop honest in sub-step 4(the last moment to activate his effect), and your opponent respond with Wrath, you may not drop another honest, consequently, your opponent can't wait until your honest resolve and drop his own honest in this sub-step. because only 1 chain can be performed in this substep.

normally, card that alter atk/def can only activated until substep3, but, Honest/Kalut has been BKSS-ed to be able to activate in substep 4 Q_Q

Aboul LaDD,and any other effect that negate an effect/summon. it have to be directly responding to what it can negate, following segoc, your LaDD will be chainlink 2, and your opponent will be chainlink 3 therefore your opponent's LaDD will resolve without effect(because his effect weren't mentioned to negate your LaDD effect), and then your own LaDD will have his atk reduced by 500 and continue to attack your opponent's LaDD.